The Mysterious Challenge Of Understanding Ice

July 24, 2012

The Mysterious Challenge Of Understanding Ice

Ice is an enigmatic, complex substance that continues to puzzle researchers, according to a review of open questions in this field

Ice is one of the best studied materials on Earth. It has shaped our planet and plays a crucial role in atmospheric and ocean physics. It is a unique ingredient in chemistry and biology as we know it would be impossible without it. Its ubiquity goes well beyond this pale blue dot: the Solar System is filled with ice.

So you could be forgiven for thinking that science’s intense focus on this material has revealed more or less all there is to know about ice–that the problem of ice is more or less solved.

Today, Thorsten Bartels-Rausch at the Paul Scherrer Institute in Switzerland and a group of pals explain why noting could be further from the truth. These guys review the frontiers of ice research and explain in fascinating detail a remarkable variety of open questions.

Their paper breaks down into questions related to: the fundamental structure of ice; its role on Earth in the air, in the sea and on land; and the part it plays on moons and comets elsewhere in the Solar System and in interstellar space.

For example, chemists still don’t understand how ice structures first form, what kind of structure occurs at the surface of ice or how this differs from the structure in the bulk.

Atmospheric physicists would dearly like to know how ice crystals grow in the atmosphere, what kind of chemistry takes place on their surface and the broader impact this has on our planet.

A better understanding of snow physics might lead to more accurate avalanche prediction. And the behaviour of sea ice–that it floats rather than sinks–must have been an important factor in the origin of life but in exactly what way?

Beyond Earth, the role of ice presents numerous challenges. For example, nobody knows what kind of ice comets are made of. Neither are they sure what kinds of ice might form on the icy moons in the outer Solar System.

Various theories suggest that Jupiter’s moon Ganymede might consist of successive layers of ices 1h, III, V, VI. By contrast, water on Earth forms exclusively type 1h ice (although some suggest that other phases might form in the Earth’s crust).

Then there are the moons with cryovolconoes, which spew out molten ice. Understanding these will be an exciting challenge for planetary geologists.

Some of these questions have important implications for humanity, particularly those relating to climate change.